Apparatus for advancing strands



Sept. 6, 1955 v. A. RAYBURN 1 APPARATUS FOR ADVANCING STRANDS Filegl July 25, 1951 3 Sheets-Sheet 1 INVENTOR VA. R YBURN 1 BY ATTORNEY Sept. 6, 1955 v. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 5 Sheets-Sheet 2 Filed July 25, 1951 lNl/EN TOR V. A. RAYBURN A r TORNEY \Kk K M wmv wm E Wk QR \\.\\\MN bk NR n Q /JY NA KA g y k 90 \QN W WWQMQ @N 93 3 Sept. 6, 1955 Filed July 25,' 1951 V. A. RAYBURN APPARATUS FOR ADVANCING STRANDS 3 Sheets-Sheet 3 FIG. 3

INVENTOR 1 A. RA YBURN ATTORNEY 2,717,125 Patented Sept. 6, 1955 APPARATUS FOR ADVANCING STRANDS Vincent A. Rayburn, Baltimore, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application July 25, 1951, Serial No. 238,546

Claims. (Cl. 242-25) This invention relates to apparatus for advancing strands, and more particularly to apparatus for advancing a plurality of strands individually at a constant linear speed and under constant tension.

In the electrolytic production of copper covered steel strands, it is desirable to advance simultaneously and continuously a plurality of steel strands individually from supply reels at a constant linear speed and under constant tension through an electroforming apparatus arranged to deposit a heavy covering of copper electrolytically on the strands. tained stationary at a point near the entrance end of the electroforming apparatus, so that the inner ends of the strands being advanced through the apparatus may be connected to the outer ends of strands wound on their respective auxiliary supply reels and thereby provide sub stantially continuous advancement of the strands through the electroforming apparatus. Since the strand supply reels are stationary, strand speed control means must be positioned adjacent to the strand supply reels to maintain the linear speed of the strands at such a speed that the advancing means maintains a predetermined tension in each strand. When a plurality of strands are involved in such a process, the strand speed control means and the strand advancing means must be arranged so that the strands may be threaded readily therethrough while other strands are being advanced through the electroplating apparatus.

An object of the invention is to provide new and improved apparatus for advancing strands.

Another object of the invention is to provide new and improved apparatus for advancing a plurality of strands individually along a predetermined path at a constant speed and under constant tension.

A strand advancing apparatus embodying certain features of the invention may include means for withdrawing a strand from a supply thereof at a predetermined linear speed, means for advancing the strand continuously from the withdrawing means along a predetermined path with a force sufiicient to tend to advance the strand at a linear speed greater than that at which it is withdrawn from said supply, and means for maintaining the linear speed of the strand at said predetermined speed with a force suificient to cause the advancing means to create a predetermined tension in the strand as it is advanced along said path.

A clear understanding of the invention will be had from the following detailed description of a specific embodiment thereof when read in conjunction with the appended drawings in which:

Fig. 1 is a schematic side elevation of a strand advanc- Usually the strand supply reels are main- Fig. 5 is a vertical section ta Fig. l.

Referring now to the drawings and more particularly to Fig. 1, there is shown a schematic arrangement of an apparatus designed to advance a plurality of steel strands -10 from left to right through an electroforming apparatus indicated generally at 12 which is designed to deen along line 5-5 of posit a heavy coating of copper electrolytically on the supply reels 23-23, positioned in strands to form copper covered steel strands 13-13. Only three of the steel strands are shown for purposes of illustrating the invention, but it is to be understood that the number of strands may be varied as desired, and may reach as high as twenty-five strands. The electroforming apparatus 12 does not form a pertinent part of the present invention and hence will be described herein only insofar as is necessary for a complete understanding of the invention.

The electroforming apparatus 12 (Figs. 1 and 2) includes an elongated trough 15, in which are positioned a series of shallow, rectangular tanks 16-16, only two complete ones of which are shown to illustrate the general construction of the electroplating apparatus. The tanks 16-16 are filled with cleaning solutions and electroplating solutions, and are arranged in the trough to electrolytically clean and pickle the steel strands 10-10 and thereafter to deposit a heavy coating of copper electrolytically on the steel strands as they are advanced through the electroforming apparatus. The strands pass under contact rollers 17-17 and over contact rollers 18- 18 journaled rotatably in the side walls of the trough 15. The rollers 17-17 and 18-18 are provided with equally spaced peripheral grooves 19-19 which maintain a pre determined spaced relationship between the strands as they are advanced through the tanks 16-16. The tanks 16-16 are connected to a positive D. C. potential, and the rollers 17-17 and 18-18 are connected to a negative D. C. potential, so that the solutions contained in the tanks 16-16 clean the steel strands electrolytically and deposit copper electrolytically on the strands to form the copper covered strands 13-13. The contact rollers 17- 17 and 18-18 are rotated by an endless chain 20 connected to be driven by an electric motor 21, so that the rollers tend to advance the strands from left to right as viewed in Fig. 1.

The steel strands 10-10 (Fig. 1) are withdrawn from a stationary manner on strands 24-24 mounted on a base 25, by a magnetic capstan'indicated generally at 28. The magnetic capstan 28 is mounted on a support 29 adjacent to the left end of'the trough 15, and is driven by an electric motor 30 at a constant rate of speed. Each individual strand 10 passes around an idler sheave 33 and a brake sheave 34 mounted on an elongated support 35. The brake sheaves 34-34 guide their respective strands to a bank of sheaves 37-37 which fan out the strands and direct them toward a bank of sheaves 38-38 mounted rotatably on a shaft 36 secured to the support 29. The sheaves 38-38 are positioned spacedly on the shaft 36 so as to space the strands 10-10 a distance apart equal to the lateral spacing of the strands on the rollers 17-17 and 18-18. The strands pass around a portion of their respective sheaves 38-38 in a counterclockwise direction (Fig. 1) and then around a substantial portion of the magnetic capstan 28 in an arc of less than 360 and in a clockwise direction. designed to grip the steel strands 10-10 magnetically in equally spaced, peripheral, substantially U-shaped grooves 39-39 (Figs. 3 and 4) provided therein as the capstan is rotated in a clockwise direction as viewed in Fig. 1 by the motor 30, and to thereby withdraw the strands 10-10 from their respective reels at a constant linear speed.

The magnetic capstan 28 is.

The supply reels 23-23 are supported in a stationary position as indicated in Fig. l, and each strand revolves around the central axis of the upper head of its respective reel as it is withdrawn therefrom. The steel strands 10-10 normally have a tendency to unwind from the reels due to the inherent resiliency of the strands and as a result, the outer convolutions on the reel tend to spring away from the reel and become entangled and break as they are withdrawn therefrom. To prevent this condition from occurring, each strand engages a guide sheave supported on the end of an arm 41 mounted rotatably on a cap 42 designed to fit neatly over the head of the reel 23 from which the strand is being withdrawn. Suitable braking means, not shown, is provided for resisting the rotation of the arm 41 with respect to the cap 42 and the reel 23 with a force sufiicient to prevent the convolutions of the strand 10 from unwinding from around the reel faster than the strand is withdrawn from the reel. The brake sheaves 34-34 mounted on the support 35 apply additional tension to their respective strands and assist the arms 41-41 in maintaining a predetermined tension on the strands between their supply reels 23-23 and the magnetic capstan 28.

The strands 10-10 (Fig. 1) pass from the magnetic capstan 28 (Figs. 1 and 2) between the contact rollers 17-17 and 18-18 of the electroforrning apparatus, and partly around a cylindrical capstan 44 mounted on the support 29 at the right hand end of the trough 15. The capstan 44 is driven by an electric motor 46, and has a plurality of equally spaced peripheral grooves 45-45 to receive the strands and to maintain the same spacing of the strands as is provided by the peripheral grooves in the rollers 17-17 and 18-18. The strands pass around a substantial portion of the capstan 44 in an arc of less than 360 and in a clockwise direction, and then partly around a bank of sheaves similar to the sheaves 33-38, one of which is shown at 47 in Fig. l. The sheaves 47-47 are mounted rotatably on a shaft 48 secured to the support 29 in the same manner that sheaves 38-38 are mounted on the shaft 36. -They direct the copper-clad strands 13-13 to a bank of sheaves 49-49 supported individually and rotatably on the support 35 so as to guide their respective strands toward sheaves 51-51 which guide their respective strand to distributing rollers 52-52 mounted on a reciprocable distributor bar 53. The bar 53 is reciprocated longitudinally by suitable means (not shown) so as to distribute the strands 13-13 uniformly across the winding surfaces of take-up reels 55-55 supported rotatably between bearings 56-56 mounted on the base 25. Each take-up reel 55 is driven by a belt 57 which engages a head pulley 58 mounted on a shaft 60 driven by an electric motor (not shown) and a tail pulley journalled on the left hand bearing 56 supporting the reel. Resiliently mounted jockey rolls 62-62 are arranged to engage the tight side of each 0 fthe belts with sufiicient pressure to permit the belts 57-57 to slip a predetermined amount with respect to their respective head pulleys, and thereby maintain a substantially uniform tension on the strands between the capstan 44 and the take-up reels 55-55 as the winding diameter of the take-up reels increases from an empty reel to a full reel. The jockey rolls may be disengaged from their respective belts to slacken the belts sufliciently to prevent the shaft 60 from rotating the reels when it is necessary to remove a full reel from the bearings 56-56 and replace it with an empty reel.

A standfby strand supply reel 23. (Fig. 5) is provided for each of the strands 10-10 to be advanced through the electroforming apparatus 12 to provide substantially continuous feeding of the strands through the electroforming apparatus. The stand-by supply reels are positioned adjacent to the reels from which the strands are being withdrawn, as shown in Fig. 5, and the inner ends of the strands being advanced through the apparatus are connected to the outer ends of the strands wound on their respective stand-by supply reels. When a strand is exhausted from its respective reel, the strand then is withdrawn from the stand-by reel. A reel having a full strand supply then is positioned on the support 25 in place of the empty reel, and the outer end thereof is connected to the inner end of the reel from which the strand is being withdrawn. Thus, a continuous supply of strands 10-10 is provided for the electroforrning apparatus 12.

The magnetic capstan 28 (Figs. 3 and 4) is designed to grip the steel strands 10-10 magnetically in the peripheral grooves 39-39, as the capstan is rotated, and to feed the strands to the capstan 44, positioned at the opposite end of the apparatus 12, at a linear speed substantially equal to the linear speed of the periphery of the grooves 39-39 of the magnetic capstan 28. The motor 46 is designed to drive the capstan 44 at a speed and with a torque which tends to advance the strands 10-10 through the electroforming apparatus at a linear speed greater than that at which they are fed thereto by the magneic capstan 28. The strands are gripped magnetically by the magnetic capstan 28 with such force that the capstan 44 cannot increase the linear speed of the strands, and consequently, the torque applied to the capstan 44 by the motor 46 exerts a predetermined tension on each of the strands as they are advanced through the electroplating apparatus 12.

The magnetic capstan 28 (Fig. 3) is a sectionalized structure in which circular end plates 65 and 66 and circular intermediate plates 67-67, made of a para-magnetic material, are keyed on a shaft 68, and are spaced apart by annular cores 70-70, also made of a paramagnetic material. The plates 67-67 and the cores 70-70 are clamped together between the end plates 65 and 66 by a plurality of tie rods 71-71. Circular bands 72-72, made of a nonmagnetic material, are fitted into annular shoulders 73-73 formed in the peripheries of the end plates 65 and 66 and the 'mtermediate plates 67-67, so that the assembly of the bands and the plates form a cylinder having a smooth outer surface. End rings 74-74 and intermediate rings 75-75, made of a mag netic material, fit neatly over the assembly of the end plates, the intermediate plates and the circular bands, and are spaced apart by thin, annular spacers 76-76 made of a nonmagnetic material. End rings 78-78, made of a nonmagnetic material, such as bronze, fit neatly over the end rings 74-74, and intermediate rings 79-79, made of the same nonmagnetic material, fit neatly over the rings 75-75.

The rings 74-74, 75-75, 78-78 and 79-79 (Figs. 3 and 4) are keyed to the end plates 65 and 66, the intermediate plates 67-67 and the annular bands 72-72 by headless set screws 80-80. The adjacent sides of these rings are beveled so that the sides of the rings and the peripheries of the spacers form the grooves 39-39 in the periphery of the magnetic capstan 28. The grooves 39-39 are designed to extend into the steel rings 74-74 and 75-75, toward the central axis of the magnetic capstan 28, a distance equal to approximately one-half the diameter of the strands 10-10 to be advanced by the capstan. Magnet coils 82-82 are positioned over the steel cores 70-70 clamped between the plates 67-67, and are connected in series with each other. One lead wire of the left hand coil 82 (Pig. 3) and one lead wire of the right hand coil 82 are connected to collector rings 84 and 85, respectively, mounted on a plate 86, made of a suitable insulating material, and secured to the shaft 68. The shaft 68 is journaled in bearings and 91 and has a sprocket 92 secured on the shaft which engages an endless chain belt 93 driven by a sprocket mounted on the shaft of the motor 30.

When a suitable D. C. potentialis applied across the collector rings 84 and 85, the magnet coils 82-82 generate magnetic flux which fiows longitudinally through the cores 70-70 radially through the plates 65 and 66 and 67-67, and longitudinally through the rings 74-74 and 75-75 so as to'form an annular magnetic field around each of the grooves 39-39. In describing the path of the magnetic flux generated by each magnet coil, the respective positions of the coils, the plates and the rings with respect to each other shall be identified by counting from left to right, as viewed in Fig. 3.

The magnet coils 82-82 may be wound around their respective cores 70-70 in such a direction, and may be connected together and to a source of D. C. potential in such a manner that the odd number coils generate a mag netic flux which travels from left to right through their respective cores, and the even number coils generate a magnetic flux which travels from right to left through their respective cores. Under these conditions the magnetic flux generated by the coils flows outward radially through the odd number intermediate plates 67-67 and inwardly radially through the end plate 65 and the even number intermediate plates 67-67 as indicated by the arrows in Figs. 3 and 4. Thus, the magnetic fiux generated by each magnet coil 82 forms an annular magnetic field around only the two grooves 39-39 which encircle the coil, and attracts only the strands engaged by these grooves. As a result, only one magnet coil is required for each pair of Wires to be advanced by the magnetic capstan 28. By virtue of this construction, the magnetic capstan 28 may be. arranged, by selection of the proper number of magnet coils, circular plates and rings, to withdraw a substantial number of steel strands -10 from their respective supply reels and feed them to the electroforming apparatus 12 and the capstan 44 at a constant linear speed.

The magnet coils are designed to generate a magnetic flux of suflicient magnitude to grip the strands and maintain the linear speed thereof substantially equal to the linear speed of the grooves of the magnetic capstan 28 at all times against a predetermined pull applied to the strands by the contact rolls 17-17 and 18-18, and the capstan 44. Due to the speed differential between the fixed speed of the strands and the magnetic capstan 28 and the no-load speed of the capstan 44, each strand is tensioned a predetermined amount by the torque applied to the capstan 44 by the motor 46.

The magnetic capstan 28 is described more fully and claimed in copending application, Serial No. 238,521, filed July 25, 1951, by D. E. Koerner for Strand Advancing Apparatus.

Operation Let it be assumed that the electroforming apparatus 12 is supplied with the proper cleaning and electroplating solutions, and that all the steel strands 10-10 to be advanced through the electroplating apparatus have been threaded from their respective supply reels around the magnetic capstan 28, between the rollers 17-17 and 18-18, around the capstan 44, and secured to their respective take-up reels 55-55. The magnet coils 82-82 are connected to a suitable D. C. potential and generate magnetic flux which attracts the wires magnetically in the grooves 39-39 of the capstan 28. The electric motors 21, 30 and 46 are energized to drive the contact rolls 17-17 and 18-18, and the capstans 28 and 44. The rotation of the magnetic capstan 28 and of the annular magnetic fields existing around the grooves 39-39 withdraws the strands 10-10 from their individual supply reels and feeds the strands to the electroforming apparatus 12 and the capstan 44 at a constant linear speed.

The motor 46 is designed to apply a torque to the capstan 44 which tends to advance the strands through the apparatus 12 at a linear speed greater than the speed at which the magnetic capstan 28 withdraws the strands from their respective supply reels and feeds them to the contact rolls 17-17 and 18-18, and the capstan 44. The motor 21 is designed to drive the contact rolls 17-17 and 18-18 with a torque and at a speed suificient to tend to advance the strands 10-10 at a linear speed greater than that at which they are withdrawn from their supply reels by the magnetic capstan 28. The magnetic capstan 28 is designed to grip the strands 10-10 magnetically with a force sufficient to prevent the strands from slipping in the grooves 39-39 of the magnetic capstan 28 when a predetermined safe pull is exerted on the strands by the contact rolls and the capstan 44. Thus, the fixed linear speed of the strands, as determined by the magnetic capstan 28, causes a predetermined slippage to occur between the individual strands and the contact rolls, and between the strands and the capstan 44. As a result, the capstan 44 and the contact rolls advance the strands 10-10 through the electroforming apparatus 12 at a constant linear speed determined by the magnetic capstan 28 and at the same time maintain a predetermined safe operating tension on each strand.

Thus, the magnetic capstan 28 acts as a speed-governing device for the strands, in that it meters the delivery of the strands to the capstan 44 at a predetermined linear speed as long as the capstan 44 applies a desired tension on the strands. If, for some reason, the capstan 44 should tension the strands above a safe operating tension, the magnetic capstan 28 is designed to let the strands slip in the grooves 39-39 to prevent the strands y from breaking.

The shaft 60 is driven by a motor (not shown) which is designed to rotate the head pulleys 58-58 secured thereon with a torque and at a speed sutlicient to rotate the take-up reels 55-55 at a speed sufiicient to tend to take up the strands 13-13 at a linear speed greater than that at which they emerge from the capstan 44 when the reels are empty. Therefore, the constant linear speed of the strands causes the belts 57-57 driving the reels to slip on their respective head pulleys a predetermined amount as soon as they start to take up the strands 13-13. This slippage is designed to be of such magnitude that it is well beyond the static friction region, and produces a substantially constant tension on the strands 13-13 as they are wound on the reels, which is substantially equal to the tension on the strands between the magnetic capstan 28 and the capstan 44.

As the winding diameter of the reels increases from an empty reel to a full reel, the speed of rotation of the reels decreases due to the constant linear speed of the strands, and as a result the slip between the belts 57-57 and their head pulleys 58-58 increases sufiiciently to maintain the required tension on the strands. The amount of belt slippage that occurs also is dependent upon the tightness of the belts 57-57. The jockey rolls 62-62 engage the tight sides of the belts, and are adjustably spring loaded to control the slippage of the belts within limits designed to suit the required tension on the strands 13-13. When a reel 55 tends to take up a strand faster than that at which it emerges from the cap stan 44, which it would as its winding diameter increases, the tension in the belts driving the reel overcomes its jockey roll momentarily and moves it in a direction to decrease the tightness of the belt. As a result, the belt slip increases momentarily and prevents the torque ap plied tothe shaft 60 from building up a tension in the strand 13 beyond a safe operating tension.

This type of drive for the take-up reels is needed in order for the contact rolls 17-17 and 18-18, and the capstan 44, to advance the strands 10-10 individually through the electroplating apparatus 12 at a constant linear speed and under a constant tension so that they receive a uniform, heavy copper coating. If the linear speed of the strands 13-13 varies substantially between the capstan 44 and the take-up reels 55-55, such variations affect the quality and thickness of the copper coating deposited on the strands.

As the strands 10-10 are withdrawn over the heads of the stationary supply reels by the magnetic capstan 28, they engage the rollers 40-40 and revolve the fiyer arms 4141 about their respective reels. The arms are provided with drag brakes (not shown) to tension the strands as they are withdrawn from the reels and prevent the outer convolutions on the reel from unwinding and becoming entangled with each other. As the strands revolve around the central axis of their respective reels, each strand receives a twist of 360 for each convolution withdrawn from the reel. This twisting of each strand between its supply reel and the magnetic capstan 28 is not of sufficient magnitude to stress the strand beyond its elastic limit. As a result, the strand is under a torsional stress which tends to cause the strand to spiral about its longiudinal axis and to coil up into short kinks if there is sufiicient slack in the strand between its reel and the magnetic capstan 28.

The braking action of the flyer arms and the braking action of the sheaves 34-34 is designed to hold the strands taut against the action of the torsional stresses in the strands, and to prevent them from kinking as they are withdrawn from the supply reels. Thus, the flyer arms, the brake sheaves and the slipping belt drive of the take-up reels 5555 enable the magnetic capstan 28, the contact rolls 1717 and 1818, and the capstan 44 to advance the strands through the electroplating apparatus at a constant linear speed at which the apparatus 12 will deposit a uniform heavy coating of copper on the strands.

It is to be understood that the term stran as used herein and in the appended claims is intended to include solid wires, stranded Wires, tubing, tapes, ribbons, and all types of metallic members of relatively smallcross section and of indefinite length having a metallic core or covering. Such strands may be made in whole or in substantial part of steel, or other suitable para-magnetic material, although for the sake of simplicity such materials are referred to herein and in the annexed claims as magnetic materials.

While the above-described method and apparatus of advancing steel strands is particularly adapted to be used in the manufacture of copper-clad steel strands, it is to be understood that it may be readily modified to advance a plurality of strands individually through various types of apparatus and processes without departing from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for advancing a strand of magnetic material at a constant speed and under constant tension from a supply thereof along a predetermined. elongated path and to a takeup, which comprises a feeding capstan for withdrawing such a strand from its supply, means for rotating the feeding capstan at a constant peripheral speed, magnetic means provided on the feeding capstan and so designed as to hold the strand magnetically against the feeding capstan with such force that the strand is advanced by said capstan at a linear speed equal to the peripheral speed of the capstan, a tensioning capstan engaged by the strand at the end of said path, and means for rotating the tensioning capstan at such a speed that it exerts a constant force on the strand to create a predetermined tension in the strand between the feeding capstan and the tensioning capstan the magnitude of which norrnally is insufiicient to cause slippage of the strand over the feeding capstan.

2. Apparatus for advancing a strand of magnetic material at a constant speed and under constant tension from a supply thereof along a predetermined elongated path and to a takeup, which comprises a magnetic capstan for withdrawing such a strand from its supply, guide means for causing the strand to engage the periphery of the capstan over an arc of less than 360, means for rotating the magnetic capstan at a constant peripheral speed, a tensioning capstan engaged by the strand at the end of said path, means for rotating the tensioning capstan at such a speed that it exerts a constant force on the strand to create a predetermined tension in the strand between the magnetic capstan and the tensioning capstan the magnitude of which normally is insufficient to cause slippage of the strand over the magnetic capstan, and guide means for causing the strand to engage the periphery of the tensioning capstan over an arc of less than 360 and for directing the strand from the tensioning capstan to the takeup.

3. Apparatus for advancing a plurality of strands of magnetic material from individual supplies thereof along equally spaced, parallel, elongated paths and to individual takeups therefor so that all the strands move at a constant and identical speed and under a constant and identical tension, which comprises a common magnetic capstan for withdrawing all of said strands simultaneously from their supplies, means for rotating the capstan at a constant peripheral speed, magnetic means provided on the capstan and so designed as to magnetically hold each strand individually against the capstan with such force that the strands are advanced by the capstan without slippage of the strands on the capstan and at a linear speed equal to the peripheral speed of the capstan, a common tensioning capstan engaged by all of said strands and positioned at the end of said path, and means for rotating the tensioning capstan at such a speed that it exerts a constant force on the strands to create a predetermined and uniform tension in all of said strands between the magnetic capstan and the tensioning capstan the magnitude of which normally is insufficient to cause slippage of the strands over the magnetic capstan.

4. Apparatus for advancing a plurality of strands of magnetic material from supplies thereof along equally spaced, parallel, elongated paths and to individual takeups therefor so that all the strands move at a constant and identical speed and under a constant and identical tension, which comprises a common magnetic capstan for withdrawing said strands simultaneously from their supplies, means for rotating the capstan at a constant peripheral speed, magnetic means associated with the capstan and so designed as to magnetically hold each strand individually against the capstan with such force that the strands are advanced by the capstan without slippage of the strands on the capstan and at a linear speed equal to the peripheral speed of the capstan, a common tensioning capstan engaged by all of said strands and positioned at the end of said paths, means for rotating the tensioning capstan at such a speed that it exerts a constant pulling force on the strands, a plurality of grooved contact rolls positioned spacedly in series intermediate of the magnetic capstan and the tensioning capstan over which the strands pass in parallel, equally spaced relationship, and means for driving said rolls at a peripheral speed in excess of the linear speed of the strands whereby said rolls contribute to the tensioning of said strands.

5. Apparatus for advancing a plurality of steel strands from individual supplies thereof along equally spaced,

parallel, elongated paths through a series of treating cells and to individual takeups therefor so that all the strands move at a constant and identical speed and under a constant and identical tension, which comprises a common magnetic capstan positioned at the beginning of said paths 2 for withdrawing such strands simultaneously from their supplies and having a plurality of equally spaced peripheral grooves for receiving said strands, guide means for causing the strands to engage their respective grooves in the magnetic capstan over arcs of considerably less than 360, means for rotating the magnetic capstan at a constant peripheral speed, magnetic means associated with the magnetic capstan and so designed as to magnetically hold each strand against the capstan in its associated groove with such force that the strands are advanced by the capstan without slippage of the strands on the capstan and at a linear speed equal to the peripheral speed of the capstan, a common tensioning capstan positioned at the end of said paths and provided with a plurality of equally spaced grooves for receiving said strands, means for tensioning the strands leaving tensioning capstan, a

9 plurality of grooved contact rolls over which said strands pass positioned spacedly in series intermediate of the mag netic capstan and the tensioning capstan and adjacent to the treating cells, and means for rotating the tensioning capstan and the contact rolls at speeds such that they exert constant predetermined pulling forces jointly on each of the individual strands.

References Cited in the file of this patent UNITED STATES PATENTS 10 Wilson Feb. 21, Karns Dec. 3, Gray Jan. 12, Symrnes Oct. 17, Franz Jan. 22, Springhorn June 11, Parvin Mar. 18, Brillhart Feb. 3, Boynton July 24, 

